Method of manufacture and operation of ribbed member for treatment of fibrous suspensions

ABSTRACT

The specification discloses a method of making, and operating, a ribbed member for the treatment of fibrous suspensions passed between the ribbed member and a corresponding ribbed member while the members rotate relatively. According to the disclosure the ribs are made from 1 1/2 to 5 times the normal heighth of ribs on such members, while the grooves between the members are partly filled with a synthetic material solidified in situ in the grooves. As the ribs wear down in operation, the height of the synthetic material in the grooves is reduced to restore the groove depth for efficient operation of the members.

United States Patent 11 1 Kurth et al.

51 July 17,1973

[75] Inventors: Klaus Kurth; Hermann Rahmig, both of Heindenheim, Germany [73] Assignee: J. M. Voith GmbH, Heidenheim (Brenz), Germany [22] Filed: Aug. 5, 1971 [21] Appl. No.: 169,182

Related US. Application Data [62] Division of Ser. No. 817,658, April 21, 1969,

abandoned.

[30] Foreign Application Priority Data Apr. 25, 1968 Germany P 17 57 328.3

[52] US. Cl 29/530, 29/424, 29/527.1, 241/260, 241/294 [51] Int. Cl B23k 19/00 [58] Field of Search 241/260, 293, 294; 29/423, 527.1, 530, 424

[56] References Cited UNITED STATES PATENTS 2,409,453 10/1946 Stuck et a1 241/260 3,059,863 10/1962 Johnson 241/294 3,278,127 10/1966 Russell 241/294 241/260 X 3,323,733 6/1967 Brown Primary ExaminerCharles W. Lanham Assistant Examiner-D. C. Reiley, Ill Att0rneyMelvin A. Crosby 57 ABSTRACT The specification discloses a method of making, and operating, a ribbed member for the treatment of iibrous suspensions passed between the ribbed member and a corresponding ribbed member while the members rotate relatively. According to the disclosure the ribs are made from 1 1/2 to 5 times the normal heighth of ribs on such members, while the grooves between the members are partly filled with a synthetic material solidified in situ in the grooves. As the ribs wear down in operation, the height of the synthetic material in the grooves is reduced to restore the groove depth for efficient operation of the members.

4 Claims, 3 Drawing Figures or bars projecting METHOD OF MANUFACTURE AND OPERATION OF RIBBED MEMBER FOR TREATMENT OF FIBROUS SUSPENSIONS RELATED APPLICATION The present application is a division of copending US. Pat. application, Ser; No. 817,658; filed: Apr. 21st, 1969, now abandoned, entitled: RIBBED MEM- BER FOR TREATMENT OF FIBROUS SUSPEN- SIONS.

The present disclosure relates to a method of making and operating apparatus fortreating fibrous matter, particularly fibrous suspension for use in the manufacture of paper, and is especially concerned with rotary devices, such as refiners.

Refiners are well knwon in the art of making paper and are employed for treating afibrous suspension before it is brought to the paper makingmachine to im'-. prove the quality of the paper made from the fibrous suspension. Such refiners comprise a pair of relatively rotatable members each having upstanding bars or ribs thereon, with a relatively small clearance defined between the tips or heads of the bars of the respective members. The fibrous suspension is caused to pass between the members while the members rotate relatively and treatment of the fibrous suspension occurs principally at the tips or heads of the ribs or barson the relatively rotating members.

Refiners, and like devices, may take the form of disc type devices in which the relatively rotatable members are in the form of discs with one thereof ordinarily being stationary and the other rotatable. The suspension to be treated is usually introduced through the center of the stationary one of the discs and moves radially outwardly between the discs while the moveable disc rotates and is treated by the bars of the discs and emerges at the peripheral portions of the discs in treated conditions.

Another type of device of this nature is a cone type refiner which has a stator in the form of a tapering cylindrical member, or frustum of hollow cone, with ribs radially inwardly therefrom. Mounted in the stator, coaxially therewith, is a rotor or plug tapered in conformity with the taper of the stator and having ribs or bars projecting radially outwardly therefrom. In this type of suspension treating device,

the suspension is introduced into the small end of the stator and flows axially therethrough while the rotor rotates wtihin the stator and effects treatment of the fibrous suspension at the. tips or heads of the aforementioned bars or ribs.

Suspensions of fibers for use in the manufacture of paper webs, and the like, are rather abrasive and the tips of the ribs or bars of the stator and rotorof such devicestend to wear down rather rapidly. The ribs or bars are formed on the members of the device by casting them integrally with the respective member and with the ribs or bars tapering outwardly from the tip or head ends thereof to the base end thereof. Heretofore, the ribs or bars have normally been, in heighth, about equal to the width thereof measured at the top or head end. Due to the aforementioned rapid wear of the ribs or bars, such devices wear out rapidly, even though provisions are made for adjustment of the relatively rotatable members of the devices toward and away from each other.

it has been proposed to increase the heighth of the ribs or barsto about twice the width thereof at the tips of the ribs or bars and this would, of course, substantially increase the useful life of the device. However, it has been found that the increased depth of the grooves between the ribs increases the energy required to drive the device because there is a greater pumping action on thefibrous suspension passing through the device. Furthermore, when deeper grooves are provided, there is lessefficiency in treatment of the suspension passing through the'device because, as mentioned, the treatment of the suspension occurs at the tip ends of the bars and the deeper grooves permit a substantially greater portion of the suspension to pass through the apparatus without treatment.

The present invention treats the problem of constructingv a fibrous suspension treating devices of the nature referred to, a refiner, for example, so as to have increased useful life while still operating efficiently and at no increase in power by forming the bars or ribs of the relatively rotating members of the device so as to be from 1.5 up to 4 or 5 times as high as the width thereof measured at the outer tip ends, and by partially filling the grooves of the members so that the projecting portion of the ribs or bars and, therefore, the free spacein the grooves, is reduced to that amount which will provide for efiicient operation of the device at no sacrifice of power. It is contemplated that the filler material disposed in the grooves will consist of a synthetic material induced into the grooves in some workable form, liquid, for example, or a paste, or a powder and, thereafter, caused to take solid formin the grooves so that the bottom portions of the grooves are effectively filled up.

It has been known in the prior art, particularly with flat conesand the like, to construct the knives or ribs or bars thereof to a substantially greater heighth than their width and to fill in the grooves located between adjacent ones thereof with wooden filler members up to a certain level along the bars. This method, while it effectively fills a portion of the grooves, requires considerable manual labor and is only practical when the grooves are more or less uniform in shape. When the bars or ribsare attached to a support member in milled slots or the like, the use of wooden filler members is not objectionable because the grooves to be filled are then relatively uniform and preshaped wooden members can be used with a fair degree of economy.

With cast members, wherein the ribs, or bars, or knives, are cast integrally with the body of the member, highly accurate dimensioning of the grooves cannot be accomplished and, furthermore, the grooves are generally in the form of a rather complicatedpattern and differ in lengths and frequently merge with each other. The filling of such grooves with wooden filler members is'totally impractical because virtually every groove requires a filling member of a special shape. In some devices, particularly steep and flat cone refiners, the bars or ribs are located at an angle with respect to the axis of rotation and have a somewhat helical configuration and in this case the grooves are particularly difficult to fill with any preshaped members such as wooden filler and installation of filler members of this nature would also be expensive and time consuming and would represent an impractical approach to the problem.

In view of the foregoing, a primary objective of the present disclosure is the provision of a method of making and operating a device for treating fibrous suspensions by means of relatively rotating ribbed members in which the device is constructed so as to have long life, while effecting efficient treatment of the suspension and without excessive use of power.

A particular object of the present disclosure is the provision of a method of making and operating a ribbed member of the nature referred to, in which the ribs of the member are formed to greater heighths than have heretofore been known while the grooves betweem the ribs are prevented from exerting a pumping action on the suspension passing through the device and thereby absorbing power.

A further object is the provision of a method of making and operating a ribbed member of the nature referred to, which is applicable to known devices.

The present disclosure may be summarized as follows:

The ribbed members of the devices are cast with the ribs thereof integral with the body thereof and from 1 1/2 to 5 times as high as is customary in the art, while the grooves between the ribs are partly filled with a plastic filler material cured, or hardened, in situ in the grooves.

The advantage of the increased heighth of the ribs is that the useful life of the ribbed members is extended substantially in proportion to the increased heighth thereof, namely, substantially from 1 1/2 to 5 times what has been known in the prior art.

The advantage of the plastic filler material in the grooves is that the pumping action of the ribbed members on the fibrous material is maintained low so that the power for driving the devices is also maintained rather low, while the fibrous material is simultaneously confined to the region of the tips of the ribs or bars where the actual treatment of the fibers occurs.

A still further advantage of the plastic filler material in the grooves is that, when the ribs of the member wear down, this material can be removed from the grooves such as by chiseling the material out if it is a hard thermal setting or curable material, or by melting if it is a thermo plastic material, or through chemical or solvent treatment. All of these removing operations are relatively simple and inexpensive as compared with the problem of removing the wooden filler members of the type referred to above. The plastic filling is removed from the grooves when the ribs or bars wear down and reduces the free depth of the grooves at the top to an amount which causes inefficient action of the device. The plastic filler material can be completely removed and replaced by a similar material in lesser amount to restore the groove depths, or the existing filler material in the grooves can merely be partially removed. When the filler material is only partly removed, it is still preferable to supply at least a cover layer of new filler material to the top thereof to provide a smooth surface for the suspension to flow over.

An advantage of the plastic filler material introduced into the grooves according to the present invention is that it completely fills the lateral space in the grooves and thus provides lateral support for the ribs or bars of the respective member. Further, the method of the present invention can be practiced with grooves of any shape and dimension, and can be employed in connection with any type of ribbed member. For disc type ribbed members, the members may be laid flat and the plastic filler material poured into the grooves in liquid form.

The plastic material may also be in the form of a paste and may be applied by spraying, by injection, or by the use of a spatula or blade. This last mentioned method would be preferred in connection with conical members because the paste would not run out of the grooves when inclined to the horizontal.

It is also possible to supply the plastic filler material to the grooves in the form of a powder which can then be caused to become molten by the application of heat. In every case, the plastic filler material is caused to harden, or solidify, in the grooves so that it becomes substantially an integral part of the respective ribbed member. Some plastic materials, such as epoxy resins, are self-curing, or can be cured by heat, while in other cases, the plastic materials are liquid or semi-liquid when in heated condition and become solid when cool. When the plastic material is of a hard type, such as epoxy resin or a polyester resin, particularly firm support for the bars or ribs is provided and the bending stress exerted on the bars or ribs at the bases thereof is correspondingly reduced.

It is contemplated that the plastic filler material may itself be filled with a material such as talcum or other known inexpensive bulk materials commonly employed for expanding plastic material volumetrically and for minimizing shrinking of the plastic material when it solidifies.

When the plastic filler material is supplied to the grooves in the form of a paste, the advantages obtained are that the material is highly viscous and does not flow in the grooves, but will remain in place even though the grooves are inverted or turned so as to extend vertically.

The exact nature of the present disclosure will be more clearly understood upon reference to the following detailed specification taken in connection with the accompanying drawings in which:

FIG. 1 is a fragmentary perspective view showing a typical disc plate for a disc refiner;

FIG. 2 is a longitudinal sectional view through the stator and rotor of a typical cone refiner; and

FIG. 3 is a sectional view, drawn at enlarged scale, and taken on line III-III of FIG. 2.

Referring to the drawings somewhat more in detail, the disc plate shown in FIG. 1 is cast from a steel alloy and comprises a body 1 having working area la on the one side formed by the peaks of ribs 2 which are cast integrally with body 1 and which form therebetween grooves 3. I

The ribs 2 taper outwardly from their outer tip ends to their bottom endsand may be, for example, 4 millimeters in width at their tips, measured in a direction lateral to the length thereof. At the lower ends of the ribs they may be, for exmaple, 6 millimeters in width. In heighth the ribs and, therefore, also the depth of the grooves 3, are about 12 millimeters which is just about 3 times the width of the tips of the ribs.

As has been explained, the depth of the grooves is so great as to introduce inefficiencies in respect of suspension treatment and power consumption and for this reason the grooves are partly filled with plastic material 4 in FIG. 1. The grooves are filled from the botton upwardly until the free space in the top of the grooves is about equal to the width of the ribs. The plastic material is introduced into the grooves while it is in a workable condition and is caused to solidify in the grooves so that it is firmly held therein by adherence to the groove surfaces and by interlocking with any surface irregularities in the groove surfaces.

The plastic filler material may be in a workable condition when it is a thermo plastic material by virtue of being heated, or it may be in the form of a powder, or a paste, or a liquid. Both thermo plastic and thermal setting resins can be applied to the grooves in the aforementioned manner and also resins which polymerize or cure such as epoxy resins, can be supplied to the grooves in liquid form.

The disc type member of FIG. 1 can be placed horizontal and the plastic filler material easily supplied to the grooves by pouring it therein.

The plastic material may itself have filler material therein in the form of bulk material such as talcum or the like to augment the volume of the plastic material thereby to reduce the cost thereof. Preferably, the plastic material is resistant to chemical attack, at least with respect to substances encountered in the treatment of fibrous suspensions to be used for making paper, and an epoxy or polyester resin is particularly advantageous in this respect. Furthermore, such resins become quite hard when cured and do not deteriorate during use of the apparatus.

When the ribs 2 are worn down to the point that the free space in the upper ends of the grooves 3 is substantially reduced below the original free depth of about 4 millimeters down to, say, about 2 millimeters, the plastic is either partly or completely removed from the grooves, to restore the free space necessary in the upper ends of the grooves. If, for example, the ribs, when the member is newly cast, are 12 millimeters in heighth, the plastic filler material in the grooves when the apparatus is first placed in use will amount to about 8 millimeters, leaving 4 millimeters free or unfilled space at the top of the grooves. When the ribs are worn down, the filler material is removed, either partially or in its entirety, by heating it up to soften it, by dissolving it with solvents, by chemically removing it, or by mechanically removing it as by chipping it out of the grooves.

The hard plastics, such as epoxy or polyester resin are preferably chipped from the grooves because they are extremely hard and chemically resistant. Thermal setting resins are also preferably chipped out of the grooves.

The plastic filler material may be removed from the grooves until the free space of about 4 millimeters is restored but, preferably, the plastic filler material is removed to beyond this level and new plastic filler material is placed in the grooves up to the level desired. With ribs 12 millimeters high, the heighth of the plastic in the grooves is, when the ribs first wear down, reduced from 8 millimeters to 4 millimeters and, subsequently, when the ribs again wear down, is removed completely from the grooves. In this manner substantially 3 times the life is obtained that can be obtained from similar ribbed members made according to the prior art.

If the depth of the grooves is only 1 1/2 times the rib width, measured at the tip end of the groove, the rib heighth and the depth of the groove will be only 6 millimeters and the heighth of the plastic filler will be only 2 1/2 millimeters. In this case, when the ribs become worn down an amount equal to about 2 millimeters, the plastic filler is completely removed from the grooves and no second filling of the grooves is carried out.

FIGS. 2 and 3 show a conical refiner in which there is a conical rotor, or plug 10, mounted on a drive shaft 9 to be driven in rotation therewith. Rotor 10 cooperates with a stator 20 fixed in a housing which is not shown. Both rotor or plug 10 and stator 20 are steel alloy castings. Rotor 10 has a peripheral face 11 facing stator 20, and stator 20 has a peripheral face 21 facing rotor 10. These surfaces have upstanding bars 12 and 22, respectively, cast integrally therewith and defining therebetween the grooves 13 and 23, respectively. According to the present disclosure, the grooves 13 and 23 are provided with plastic filling material 14 and 24, respectively, extending from the bottoms of the grooves upwardly to leave a freeor unfilled space at the tops of the grooves about equal in depth to the width of the ribs at their tip ends.

In the case of both the disc type and cone type refiner, the rotatable elements thereof are adjustable to vary the distance between the rotor and-stator of the device and this adjustability is availed of for compensating for wear of the ribs of the rotor and stator which takes place during operation of the apparatus.

The disclosure is capable of modification within the scope of the appended claims.

What is claimed is:

l. The method of fabricating and operating an apparatus for the treatment of fibrous suspensions, the apparatus including a pair of relatively rotatable members having surfaces in substantially parallel spaced relation with ribs upstanding from each said surface in distributed relation and forming grooves therebetween, the tips of the ribs on the respective members passing closely by each other as the members rotate relatively and thereby effecting the treatment of fibrous suspension flowing between said members, the said method comprising: forming said ribs to a height within the range of about 1.5 to about 5.0 times the width of the ribs at the tips thereof, filling in the grooves between the ribs from the bottom of the grooves partway up to the tips of the ribs with a plastic filler material which is introduced into said grooves in a workable condition which and is caused to solidify in situ in said grooves, and reducing the height of the filler material in said grooves when the tips of said ribs wear down during use of the apparatus to the point the unfilled portion of the grooves is substantially diminished thereby to restore the unfilled portion of said grooves substantially to the original depth thereof.

2. The method according to claim 1, which includes incorporating a filler in said plastic material.

3. The method according to claim 1, which includes selecting said plastic material from the class of synthetic resins which includes epoxy resin and which becomes solidified by reason of a hardening agent added thereto and which is resistant to chemical attack.

4. The method according to claim 1 in which the said ribs are so distributed that the said grooves formed therebetween are nonuniform in respect of at least the length thereof. 

1. The method of fabricating and operating an apparatus for the treatment of fibrous suspensions, the apparatus including a pair of relatively rotatable members having surfaces in substantially parallel spaced relation with ribs upstanding from each said surface in distributed relation and forming grooves therebetween, the tips of the ribs on the respective members passing closely by each other as the members rotate relatively and thereby effecting the treatment of fibrous suspension flowing between said members, the said method comprising: forming said ribs to a height within the range of about 1.5 to about 5.0 times the width of the ribs at the tips thereof, filling in the grooves between the ribs from the bottom of the grooves partway up to the tips of the ribs with a plastic filler material which is introduced into said grooves in a workable condition which and is caused to solidify in situ in said grooves, and reducing the height of the filler material in said grooves when the tips of said ribs wear down during use of the apparatus to the point the unfilled portion of the grooves is substantially diminished thereby to restore the unfilled portion of said grooves substantially to the original depth thereof.
 2. The method according to claim 1, which includes incorporating a filler in said plastic material.
 3. The method according to claim 1, which includes selecting said plastic material from the class of synthetic resins which includes epoxy resin and which becomes solidified by reason of a hardening agent added thereto and which is resistant to chemical attack.
 4. The method according to claim 1 in which the said ribs are so distributed that the said grooves formed therebetween are nonuniform in respect of at least the length thereof. 